wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
object Item {{ def main(args: Array[String]) = println("info") }} | object Item {{ def main(args: Array[String]): Unit = println("info") }} | Add return type Unit. | Scala |
if item = 44: | if item == 44: | Use == for comparison. | Python |
val foo: Int = 'output' | val foo: String = 'output' | Fix type. | Kotlin |
<a href='https://demo.net' target='_blank'> | <a href='https://demo.net' target='_blank' rel='noopener'> | Add rel for security. | HTML |
if (bar = 75) {{}} | if (bar === 75) {{}} | Use === for equality. | JavaScript |
fs.readFile('input.csv', (err,data) => {{ if(err) throw err; }}); | fs.readFile('input.csv', (err,data) => {{ if(err) {{ console.error(err); return; }} }}); | Better error handling. | Node.js |
status: info
value: test, | status: info
value: test | Remove comma. | YAML |
const num = 22; num = 62; | let num = 22; num = 62; | Cannot reassign const. | JavaScript |
type MyType = string | number; let x: MyType = true; | type MyType = string | number; let x: MyType = 'hello'; | Type not in union. | TypeScript |
data[80] | if (data.indices.contains(80)) data[80] | Check index. | Kotlin |
int &ref; | int x; int &ref = x; | Reference must be initialized. | C++ |
UPDATE users SET status='hello' WHERE role=81 | UPDATE users SET status='hello' WHERE role=81; | Add semicolon. | SQL |
<person age=33> | <person age="33"> | Quote attribute. | XML |
baz | baz() | Add parentheses. | Swift |
<?php
// code
?> | <?php
// code
?> | Correct. | PHP |
fn baz() -> i32 {{ 50 }} | fn baz() -> i32 {{ 50 }} | Correct. | Rust |
for i=1,55 do print(i) end | for i=1,55 do print(i) end | Correct. | Lua |
'info' + 98 | 'info' + str(98) | Can't add int to string. | Python |
def bar
puts 'info'
end | def bar
puts 'info'
end | Correct. | Ruby |
const p:Person = {{name:'hello'}}; | const p:Person = {{name:'hello', age:76}}; | Add missing property. | TypeScript |
$val = 50; if ($val = 50) {{}} | $val = 50; if ($val == 50) {{}} | Use ==. | PHP |
let val = 31; let val = 37; | let val = 31; val = 37; | Duplicate declaration. | JavaScript |
Write-Host 'info' | Write-Host 'info' | Correct. | PowerShell |
function handle(): void {{ return 25; }} | function handle(): number {{ return 25; }} | Return type mismatch. | TypeScript |
function handle(val)
print(val)
end | function handle(val)
print(val)
end | Correct. | Lua |
if (a = 84) | if (a == 84) | Use ==. | R |
let c: number = 'result'; | let c: string = 'result'; | Fix type. | TypeScript |
test | test() | Add parentheses. | Kotlin |
console.log('result' | console.log('result') | Close parenthesis. | JavaScript |
int data = 'info'; | String data = 'info'; | Type mismatch. | Dart |
const http = require('http'); http.createServer((req,res) => res.end('info')).listen(22); | const http = require('http'); http.createServer((req,res) => res.end('info')).listen(22); | Correct. | Node.js |
with open('config.json') as fp:
data = fp.read() | with open('config.json') as fp:
data = fp.read() | Correct. | Python |
cin >> foo; | int foo;
cin >> foo; | Declare variable. | C++ |
if x > 22
print('value') | if x > 22:
print('value') | Colon missing after if. | Python |
raise 'data' | raise Exception('data') | Raise needs an exception class. | Python |
for bar in range(55)
print(bar) | for bar in range(55):
print(bar) | Colon after for. | Python |
List<int> list = [1,2,3]; | List<int> list = [1,2,3]; | Correct. | Dart |
object Product {{ def main(args: Array[String]) = println("info") }} | object Product {{ def main(args: Array[String]): Unit = println("info") }} | Add return type Unit. | Scala |
[75, 38, 13 | [75, 38, 13] | Close bracket. | Ruby |
let mut result=10; let r1=&mut result; let ref2=&mut result; | let mut result=10; {{ let r1=&mut result; }} let ref2=&mut result; | Only one mutable borrow. | Rust |
package main
func main() {{}} | package main
import 'fmt'
func main() {{}} | Import needed. | Go |
def foo():
print('message') | def foo():
print('message') | Indent function body. | Python |
class Person {{ int temp; }}
obj.temp=5; | class Person {{ public int temp; }}
obj.temp=5; | Make field public. | Java |
list:
- item1
- item2 | list:
- item1
- item2 | Correct. | YAML |
fs.readFile('log.txt', (err,data) => {{ if(err) throw err; }}); | fs.readFile('log.txt', (err,data) => {{ if(err) {{ console.error(err); return; }} }}); | Better error handling. | Node.js |
if (index = 67) | if (index == 67) | Use ==. | C++ |
[x*x for x in list if x > 55] | [x*x for x in list if x > 55] | Correct list comprehension. | Python |
int* p = nullptr; *p=5; | int* p = new int; *p=5; | Allocate memory. | C++ |
val count: Int = 'result' | val count: String = 'result' | Fix type. | Kotlin |
while result > 72
result -= 1 | while result > 72:
result -= 1 | Colon missing after while. | Python |
let text = String::from("output"); let r=&text; text.push_str("!"); | let mut text = String::from("output"); let r=&text; println!("{{}}", r); text.push_str("!"); | Cannot mutate while borrowed. | Rust |
if c = 9 | if c == 9 | Use ==. | MATLAB |
values[22] | if (length(values) >= 22) values[22] | Check length. | R |
System.out.println('output') | System.out.println('output'); | Add semicolon. | Java |
if z = 42 {{}} | if z == 42 {{}} | Use ==. | Swift |
disp('message') | disp('message') | Correct. | MATLAB |
// comment | /* comment */ | Use /* */. | CSS |
<br></br> | <br> | Self-closing. | HTML |
local data = 35 | local data = 35 | Correct. | Lua |
yield val | yield val | Correct yield. | Python |
if (val = 53) {} | if (val == 53) {} | Use ==. | Dart |
x <- 5; if (x > 3) print('large') | x <- 5; if (x > 3) print('large') | Correct. | R |
name: value
age: 69 | name: value
age: 69 | Correct. | YAML |
function foo() {{
return
{{key:'info'}}
}} | function foo() {{
return {{key:'info'}};
}} | Return object on same line. | JavaScript |
int[] values = new int[27];
values[27] = 5; | int[] values = new int[27];
if (27 < values.length) values[27] = 5; | Check bounds. | Java |
let text1 = String::from("output"); let text2 = text1; println!("{{}}", text1); | let text1 = String::from("output"); let text2 = text1.clone(); println!("{{}}", text1); | Clone to avoid move. | Rust |
echo message test | echo 'message test' | Quote to prevent splitting. | Shell |
class = 'hello' | class_name = 'hello' | 'class' is a keyword. | Python |
INSERT INTO users VALUES ('message',56) | INSERT INTO users (age, role) VALUES ('message',56); | Specify columns. | SQL |
try:
x = 1 / 0
except
pass | try:
x = 1 / 0
except Exception:
pass | Specify exception type. | Python |
List(49,62,16) | List(49,62,16) | Correct. | Scala |
<p>message <b>test</p></b> | <p>message <b>test</b></p> | Nest properly. | HTML |
<hr></hr> | <hr> | Self-closing. | HTML |
<div><p>message</div></p> | <div><p>message</p></div> | Nest properly. | HTML |
<input type='text' value='output'> | <input type='text' value='output' name='status'> | Add name attribute. | HTML |
values[46] | if values.indices.contains(46) {{ values[46] }} | Check index. | Swift |
.Item {{ color: blue; }} | .Item {{ color: blue; }} | Correct. | CSS |
["value", 41] | ["value", 41] | Correct. | JSON |
h1 {{ font-size:57px color:blue; }} | h1 {{ font-size:57px; color:blue; }} | Add semicolon. | CSS |
<person name='output'/> | <person name="output"/> | Double quotes. | XML |
let v=vec![52,58,9]; let primary=&v[0]; v.push(56); | let mut v=vec![52,58,9]; let primary=v[0]; v.push(56); | Copy instead of reference. | Rust |
def process(a):
return a + 1 | def process(a):
return a + 1 | Correct. | Python |
print('data') | print('data') | Correct. | R |
int x; System.out.println(x); | int x = 0; System.out.println(x); | Initialize variable. | Java |
<root><child>text</child></root> | <root><child>text</child></root> | Correct. | XML |
<a href='https://test.org' target='_blank'> | <a href='https://test.org' target='_blank' rel='noopener'> | Add rel for security. | HTML |
User.save(); | User.save().then(()=>{{}}).catch(err=>{{}}); | Handle promise. | Node.js |
SELECT * FROM users WHRE email=85; | SELECT * FROM users WHERE email=85; | Fix WHERE. | SQL |
my @arr = (13,99,4); | my @arr = (13,99,4); | Correct. | Perl |
$x = 5; if ($x -eq 5) { Write-Host 'yes' } | $x = 5; if ($x -eq 5) { Write-Host 'yes' } | Correct. | PowerShell |
div {{ color=#fff; }} | div {{ color: #fff; }} | Use colon. | CSS |
if bar = 55 | if bar == 55 | Use ==. | Ruby |
const num = 8; num = 6; | let num = 8; num = 6; | Cannot reassign const. | JavaScript |
void bar();
int main(){{bar();}} | void bar(); // prototype
int main(){{bar();}} | Declare before use. | C++ |
random.sqrt(59) | import random
random.sqrt(59) | Import module first. | Python |
const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('info')); app.listen(30); | const express = require('express'); const app = express(); app.get('/', (req,res) => res.send('info')); app.listen(30, () => console.log('listening')); | Add callback. | Node.js |
JOIN orders ON users.id = orders.name | JOIN orders ON users.id = orders.name | Correct. | SQL |
#content {{ color: green; }} | #content {{ color: green; }} | Correct. | CSS |
if (c) console.log('yes') else console.log('no') | if (c) console.log('yes'); else console.log('no'); | Missing semicolon. | JavaScript |
x > 28 & a < 7 | x > 28 and a < 7 | Use 'and' not '&'. | Python |
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